A blood test could detect about half of lung cancers up to five years before other tests, according to a team of British scientists.

In a series of papers to be presented Sunday at the annual meeting of the American Society of Clinical Oncology in Chicago, the scientists from the company Oncimmune tout their "Early CDT-Lung Test" for finding around 40 percent of lung cancers years before they show up on CT scans.

The company hopes the test, commercially available in the United States starting Tuesday, will not only save lives by detecting cancer early, but drive down health care costs.

The test works by looking for antibodies, called auto-antibodies, which the body produces to combat cancer.

As Geoffrey Hamilton-Fairley, executive chairman of Oncimmune, explained to DOTmed News, cancer cells divide rapidly. During division, they release antigens that the body recognizes as foreign, which it combats with auto-antibodies.

"Everybody has a background count of these auto-antibodies," Hamilton-Fairley said, which actually increase as we age, possibly because our bodies are fighting off many less aggressive cancers successfully.

The research originated with John Robertson, a professor at the University of Nottingham. As part of their yearly check-up, his patients at high-risk for breast cancer had their blood drawn. If they came down with cancer, Robertson went back to their blood samples and retroactively tested them for the auto-antibodies, finding that over half of the cancers could have been found four years before diagnosis.

For the current test, patients have their blood samples mailed to Oncimmune's U.S. testing facility in De Soto, Kan., just outside Kansas City.

The researchers then choose a selection of around six antigens that they pass a patient's blood sample over. If auto-antibodies are present, they'll bind to the antigens. After doing this a few times for accuracy, researchers develop the patient's antigen "fingerprint." This fingerprint is then compared against a population cut-off to judge the patient's risk for developing cancer.

Eventually, physicians will compare a patient's fingerprint against those taken from previous years, and not just population cut-offs, for more accurate readings, Hamilton-Fairley said.

"We'll end up with your own individual antigen fingerprint," he said, "and you'll be able to compare that year by year, and over time you'll pay more attention if you stray from the personal profile."

For now, they recommend one test about every five years, but as the patient ages or if there are risk factors - specifically, smoking - doctors might look at it more often.

PAPERS AT ASCO

On Sunday at ASCO, Oncimmune will share results from the most recent research on the test. Two presentations indicate its reliability, with one presentation suggesting the test works across ethnicities and with different demographics, and another that multiple samples from the same person match up with each other.

The company is also releasing the latest data on the test's accuracy. In this study, the researchers examined 500 cancer patients using the Early CDT Lung test.

The results resemble those found in a technical paper published February in the Annals of Oncology, which looked at collections of 12,000 patient samples with over 80,000 assays, Hamilton-Fairley said.

For lung cancer, the test has around 40 percent sensitivity and 90 percent specificity, with an overall accuracy of 88 percent, he said, which he thinks surpasses that of lung CT scans.

The test, designed for solid tumors, picks up all stages of the disease about equally, Hamilton-Fairley said. And a study conducted by the Mayo Clinic found it could find lung cancer about half a decade before a CT scan would pick up a nodule.

But Hamilton-Fairley believes that the most accurate results might come from using CT scans and the blood together. If a CT scan uncovers a nodule, the patient would then undergo an Early CDT test.

"If a nodule is picked up by a CT scan and there's a positive test, the risk of cancer increases three and a half times," Hamilton-Fairley said. "It's a very useful risk stratification tool."

While the lung cancer test is the first out of the gate, a breast cancer test could be available by the middle of next year.

"Our scientific advisory board believed [lung cancer] had the biggest need. It's the biggest cancer killer by miles, and there's nothing else," Hamilton-Fairley said.

Lung cancer takes a huge human and financial toll. It's the leading cause of cancer-related deaths in the United States, killing nearly 160,000 people in 2009, according to the National Cancer Institute. And the price of treating lung cancer victims in the United States amounts to around $10 billion a year.

That's partly why Oncimmune hopes to make the economic case for the test, which costs $475. In a separate presentation at ASCO, Oncimmune discusses a model which suggests using the test with CT scans is cost-effective.

Currently, the test is reimbursed by some health plans in the U.S. and Medicare Part B, although it's not reimbursed by the National Health Service in the United Kingdom yet, Hamilton-Fairley said.

As the technological requirements are fairly low, the test could also be useful in middle and low income countries, according to Oncimmune, where about half of all cancers will be diagnosed in the coming decades.